#include "zutil.h"

#ifndef NO_DUMMY_DECL
struct internal_state      {int dummy;}; /* for buggy compilers */
#endif

const char * const z_errmsg[10] = {
  "need dictionary",     /* Z_NEED_DICT       2  */
  "stream end",          /* Z_STREAM_END      1  */
  "",                    /* Z_OK              0  */
  "file error",          /* Z_ERRNO         (-1) */
  "stream error",        /* Z_STREAM_ERROR  (-2) */
  "data error",          /* Z_DATA_ERROR    (-3) */
  "insufficient memory", /* Z_MEM_ERROR     (-4) */
  "buffer error",        /* Z_BUF_ERROR     (-5) */
  "incompatible version",/* Z_VERSION_ERROR (-6) */
  ""
};


const char * ZEXPORT zlibVersion() {
  return ZLIB_VERSION;
}

uLong ZEXPORT zlibCompileFlags() {
  uLong flags;
  flags = 0;
  switch( sizeof( uInt ) ) {
    case 2:
      break;
    case 4:
      flags += 1;
      break;
    case 8:
      flags += 2;
      break;
    default:
      flags += 3;
  }
  switch( sizeof( uLong ) ) {
    case 2:
      break;
    case 4:
      flags += 1 << 2;
      break;
    case 8:
      flags += 2 << 2;
      break;
    default:
      flags += 3 << 2;
  }
  switch( sizeof( voidpf ) ) {
    case 2:
      break;
    case 4:
      flags += 1 << 4;
      break;
    case 8:
      flags += 2 << 4;
      break;
    default:
      flags += 3 << 4;
  }
  switch( sizeof( z_off_t ) ) {
    case 2:
      break;
    case 4:
      flags += 1 << 6;
      break;
    case 8:
      flags += 2 << 6;
      break;
    default:
      flags += 3 << 6;
  }
  #ifdef DEBUG
  flags += 1 << 8;
  #endif
  #if defined(ASMV) || defined(ASMINF)
  flags += 1 << 9;
  #endif
  #ifdef ZLIB_WINAPI
  flags += 1 << 10;
  #endif
  #ifdef BUILDFIXED
  flags += 1 << 12;
  #endif
  #ifdef DYNAMIC_CRC_TABLE
  flags += 1 << 13;
  #endif
  #ifdef NO_GZCOMPRESS
  flags += 1L << 16;
  #endif
  #ifdef NO_GZIP
  flags += 1L << 17;
  #endif
  #ifdef PKZIP_BUG_WORKAROUND
  flags += 1L << 20;
  #endif
  #ifdef FASTEST
  flags += 1L << 21;
  #endif
  #ifdef STDC
  #  ifdef NO_vsnprintf
  flags += 1L << 25;
  #    ifdef HAS_vsprintf_void
  flags += 1L << 26;
  #    endif
  #  else
  #    ifdef HAS_vsnprintf_void
  flags += 1L << 26;
  #    endif
  #  endif
  #else
  flags += 1L << 24;
  #  ifdef NO_snprintf
  flags += 1L << 25;
  #    ifdef HAS_sprintf_void
  flags += 1L << 26;
  #    endif
  #  else
  #    ifdef HAS_snprintf_void
  flags += 1L << 26;
  #    endif
  #  endif
  #endif
  return flags;
}

#ifdef DEBUG

#  ifndef verbose
#    define verbose 0
#  endif
int z_verbose = verbose;

void z_error( m )
char *m;
{
  fprintf( stderr, "%s\n", m );
  exit( 1 );
}
#endif

const char * ZEXPORT zError( err )
int err;
{
  return ERR_MSG( err );
}

#ifndef HAVE_MEMCPY

void zmemcpy( dest, source, len )
Bytef* dest;
const Bytef* source;
uInt  len;
{
  if( len == 0 ) {
    return;
  }
  do {
    *dest++ = *source++; /* ??? to be unrolled */
  } while( --len != 0 );
}

int zmemcmp( s1, s2, len )
const Bytef* s1;
const Bytef* s2;
uInt  len;
{
  uInt j;
  for( j = 0; j < len; j++ ) {
    if( s1[j] != s2[j] ) {
      return 2 * ( s1[j] > s2[j] ) - 1;
    }
  }
  return 0;
}

void zmemzero( dest, len )
Bytef* dest;
uInt  len;
{
  if( len == 0 ) {
    return;
  }
  do {
    *dest++ = 0;  /* ??? to be unrolled */
  } while( --len != 0 );
}
#endif


#ifdef SYS16BIT

#ifdef __TURBOC__
/* Turbo C in 16-bit mode */

#  define MY_ZCALLOC

/* Turbo C malloc() does not allow dynamic allocation of 64K bytes
  and farmalloc(64K) returns a pointer with an offset of 8, so we
  must fix the pointer. Warning: the pointer must be put back to its
  original form in order to free it, use zcfree().
*/

#define MAX_PTR 10
/* 10*64K = 640K */

local int next_ptr = 0;

typedef struct ptr_table_s {
  voidpf org_ptr;
  voidpf new_ptr;
} ptr_table;

local ptr_table table[MAX_PTR];
/* This table is used to remember the original form of pointers
  to large buffers (64K). Such pointers are normalized with a zero offset.
  Since MSDOS is not a preemptive multitasking OS, this table is not
  protected from concurrent access. This hack doesn't work anyway on
  a protected system like OS/2. Use Microsoft C instead.
*/

voidpf zcalloc( voidpf opaque, unsigned items, unsigned size ) {
  voidpf buf = opaque; /* just to make some compilers happy */
  ulg bsize = ( ulg )items * size;
  /* If we allocate less than 65520 bytes, we assume that farmalloc
    will return a usable pointer which doesn't have to be normalized.
  */
  if( bsize < 65520L ) {
    buf = farmalloc( bsize );
    if( *( ush* )&buf != 0 ) {
      return buf;
    }
  } else
  { buf = farmalloc( bsize + 16L ); }
  if( buf == NULL || next_ptr >= MAX_PTR ) {
    return NULL;
  }
  table[next_ptr].org_ptr = buf;
  /* Normalize the pointer to seg:0 */
  *( ( ush* )&buf + 1 ) += ( ( ush )( ( uch* )buf - 0 ) + 15 ) >> 4;
  *( ush* )&buf = 0;
  table[next_ptr++].new_ptr = buf;
  return buf;
}

void  zcfree( voidpf opaque, voidpf ptr ) {
  int n;
  if( *( ush* )&ptr != 0 ) { /* object < 64K */
    farfree( ptr );
    return;
  }
  /* Find the original pointer */
  for( n = 0; n < next_ptr; n++ ) {
    if( ptr != table[n].new_ptr ) {
      continue;
    }
    farfree( table[n].org_ptr );
    while( ++n < next_ptr ) {
      table[n - 1] = table[n];
    }
    next_ptr--;
    return;
  }
  ptr = opaque; /* just to make some compilers happy */
  Assert( 0, "zcfree: ptr not found" );
}

#endif /* __TURBOC__ */


#ifdef M_I86
/* Microsoft C in 16-bit mode */

#  define MY_ZCALLOC

#if (!defined(_MSC_VER) || (_MSC_VER <= 600))
#  define _halloc  halloc
#  define _hfree   hfree
#endif

voidpf zcalloc( voidpf opaque, unsigned items, unsigned size ) {
  if( opaque ) {
    opaque = 0;  /* to make compiler happy */
  }
  return _halloc( ( long )items, size );
}

void  zcfree( voidpf opaque, voidpf ptr ) {
  if( opaque ) {
    opaque = 0;  /* to make compiler happy */
  }
  _hfree( ptr );
}

#endif /* M_I86 */

#endif /* SYS16BIT */


#ifndef MY_ZCALLOC /* Any system without a special alloc function */

#ifndef STDC
extern voidp  malloc OF( ( uInt size ) );
extern voidp  calloc OF( ( uInt items, uInt size ) );
extern void   free   OF( ( voidpf ptr ) );
#endif

voidpf zcalloc( opaque, items, size )
voidpf opaque;
unsigned items;
unsigned size;
{
  if( opaque ) {
    items += size - size;  /* make compiler happy */
  }
  return sizeof( uInt ) > 2 ? ( voidpf )malloc( items * size ) :
         ( voidpf )calloc( items, size );
}

void  zcfree( opaque, ptr )
voidpf opaque;
voidpf ptr;
{
  free( ptr );
  if( opaque ) {
    return;  /* make compiler happy */
  }
}

#endif /* MY_ZCALLOC */
